We can all only speak from our personal experiences and preferences Nodnerb. It will all depend on what you think you prefer out of the pros and cons of each system.
I am still new so I don't have a lot of experience to tell you, but I'll share what I know.
I started with the 801 penstyle. That was a horrible decision for me. Its not really upgradable and I wasn't aware that I would need to constantly top off the cartridges or drip every 5 puffs or so, nor that I'd be constantly recharging one battery or another (one battery would last 2 hours).
I learned my lesson at that point and figured out a little better what I needed and wanted and read a ton of reviews and posts and videos and everything I could imagine. It is all about personal preference and need. It was pretty easy to narrow my choice down to the 501 or ego system as they are so popular and both can be upgraded and have many different options to try.
In the end I went with the Ego-T (type B) because I wanted a good long lasting battery and I didn't want to fuss with dripping or topping off, and I liked the volume the tank held. I also knew that if I wanted to try a cartomizer with the ego battery, I easily could without having to order another whole kit.
There are pros and cons to each setup, so you have to try to determine what is most important to you. It can be hard without any experience. The reason I went with the 801 penstyle first was because I was afraid the Ego would be too large, would look like a cigar, and wasn't lady-like enough. After using the 801 and struggling with it those reasons I *thought* were important to no longer were... I wanted something reliable and easy without a lot of fuss.
So as far as the "leaking" with the Ego T tanks... that seems to mainly be a problem of the past. They know now that using the silicone caps instead of the plastic caps works better. Also they sell replacement caps on the cheap (5 for $1.50) so that you can reuse your tank but you can have a fresh cap every time which also keeps a better seal and less leaking. And I don't know about anyone else but with the 100% PG juice I've had that stuff is so thin that if I hold the bottle that it came in upside down with the cap on, it'll leak out of that! So maybe try some juices that have up to 20-30% VG in them. (I've used the straight 100% PG in my tank and not had any leaks)
One battery lasts me all day and with the larger size tank on the type B, one filled tank lasts me all day as well. I like the ease of the use, but that's me. Also to fill the tank you just pour your juice into it instead of having to use syringes or different methods anything like that. Its super easy.
BUT I do also have my 801 to drip on to try flavors, so it serves a purpose and as a backup as well.
Hope something I've said helps you in some way instead of just mashing more confusion in your brain
Good luck!
Personally I'd go for (and this is what I bought.... ) The Ego-T (type B) kit (with one SR and one LR atomizer-if your vendor gives you that choice-, empty tanks), extra tank caps, a couple cartomizers, and several small bottles of juice to sample.
